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WI H. GOODALE AND IVI. LIBULLAHD.

CARBUHETER. APPLICATION FILED MAR. 2a. 1917.

Patented June 10,19l9.

MMI

WARD R. GOODALE AND MAURICE L. B ASSIGNORS, BY DIRECT AND MESNE ULLARD, OF CHESTER, NEW HAMPSHIRE, ASSIGNMENTS, TO ISOTHERMAL CARBURETOR COMPANY, 0F PORTSMOUTH, NEW HAMPSHIRE, A. CORPORATION 0F MAINE.

CARBURETER.

Leucate. y

Specification. of Letters Patent.

Patented J une td', 1919.

Application led March 23, 1917. Serial No. 156,841.

To all whom t may concern.'

Be it known that we, WARD R. GooDALn and MAURICE L. BULLARD, citizens of the United States, residing at Manchester, in the county of Hillsboro and State of New Hampshire, have invented certain new and useful Improvements in Carbureters; and We do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains .to make and use the same.

The present invention relates to carbureters and more particularly to carbureters employed for handling the heavier grades of liquid fuel.

One object of the present invention is to provide an improved construction for effectually heating the liquid fuel and air mixed therewith through the medium of the exhaust gases.

Another object of the invention is to provide an improved form of carbureter which supplies a variable mixture of air and liquid fuel to the motor controlled by the suction in the mixing chamber.

With these objects in view -the several features of the invention consist in certain novel features of construction, combinations and arrangements of parts hereinafter described and claimed, the advantages of which will be obvious to those skilled in the art from the following description.

The accompanying drawing represents a longitudinal section in elevation of a carbureter embodying the several features of the invention.

According to the present invention the incoming air is first heated initially by the exhaust gases and this heated air is then passed through the ioat chamber to cause a preliminaryheating of the liquid fuel. A final heating of the fuel and air in the mixing chamber is accomplished by surrounding thechamber with a heating chamber into which the exhaust gases pass after heating the air. With thisconstruction the heat in the exhaust gases is effectually utilized and4 the gasolene or other liquid fuel is completely vaporized.

In the illustrated embodiment of the inventlon the air enters the carbureter through a vertical air passage 5 having an opening at the top controlled by a butteriiy valve 6.

Located in the carbureter casing beneath the air passage 5 is a chamber 7 provided with the usual ring float 8 supported upon one end of a pivoted lever 9 having its opposite end connected to a float valve 10 which controls the supply of liquid through the passage 11. From an inspection of the drawing it will be noted that the iioat valve is provided with an elongated stem having a ball-shaped upper end 12 clamped in a supporting block 13 by a threaded plug 14:. This construction causes the float valve to be moved vertically by the annular float and at the same time permits angular movements of the valve 1n order that the latter may be properly seated. -The valve is of conical form and in order 'to prevent complete disengagement of the valve from the seat a short attenuated stem 15 the valve into the vertical portion of the fuel passage. The liquid contained in the float chamber is heated by the passage of the incoming air therethrough and to this end a tube 17 passes centrally through the ioat chamber from top to bottom. This tube forms a continuation of the air passage 5 and connects the latterl with an air passage 19 formed in the bottom of the carburetor casing. The incoming airis initially heated through the provision of one or more tubes 20 extending transversely of the air passage 5. These tubes communicate with a branch pipe 22 extending from the usual exhaust pipe of the motor and threadedly secured to the side of the carbureter casing, as shown clearly in the drawing. The passage of exhaust gases through this pipe 22 is controlled by a pivoted valve 23.

The fuel is conveyed from the iioat chamber to a primary nozzle 25 through the fuel passage 26 which it will be noted passes through and adjacent to the 'heated air sage to prevent cooling of the fuel. The nozzle 25 is positioned in the restricted portion of a Venturi tube 27 so that the air rushing through the tube will thoroughly mix projects from the end of.

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. with the'atomized fuel. The flow of liquid n then delivered through the nozzle is controlled in the usual manner by a needle valve 29 threaded in a block 30 and having a knurled' end 31 by lwhich it may be conveniently 4operated. Under certain conditions it is desirable to provide for the operation of a. secondary nozzle indicated at 32 and positioned in a Venturi tube 33. This secondary nozzle is supplied with liquid from the common fuel passage 26. It Will be observed from the. drawing that the air passage 19 formed in the bottom of the carbureter casing is in communication with the lower ends of both Venturi tubes 27 and 33. It is desirable to heat the explosive mixture formed at both the primary and secondary nozzles and to this end the tubes 20 communicate with a heating chamber 35 formed in the carburet-er casing and completely surrounding the Venturi tubes and the passages leading therefrom to the intake manifold. In order to provide-for a continuous circulation of exhaust gases through the carbureter the heating chamber 35 communicates with a discharge pipe through an opening indicated at 3 lVith this construction the air is initially heated from the exhaust gases and in turn heats the liquid fuel during its passage therethrough. The heated air and fuel are to the mixing chamber and are further heated during the mixing process and thereafter' by the exhaust gases which pass into the chamber 35 after initially heating the air. It may be noted that independently vof the heat imparted to the air and liquid fuel from the exhaust gases one important desidera-tum of `this construction is that all of the walls of the carbureter with which the mixture comes in contact are maintained at a sufficiently high temperature to prevent condensation of the liquid.

With this construction, therefore, it is assured that the liquid is not only thoroughly atomized initially but that it remains in this condition.

According to the present invention When the suction in the mixing chamber is at ay minimum, as when the motor is idling, fuel and air are supplied only through the Venturi tube 27. When the suction increases slightly and during normal operating condit-ions this mixture 1s supplemented by air 55' delivered through the Venturi tube V33 and when the suction is greatest the mixture from the primary nozzle is supplemented by both air and fuel from the secondary nozzle. To this end con'mmnication between the Venturi tube 33 and the passage 38 leading therefrom is normally closed by a disk valve 40 seated upon the top of the tube. This valve is mounted upon a stem 41 and is normally retained in closed position by a light ,end 4S forminga spring 42. The end of the stem 41 is provided with an elongated portion 44 having a tapered end 45 adapted to enter the passage in the upper end of the secondary nozzle 32. The formation of the end 45 is such that the initial opening movement of the valve 4() does not permit the flow of liquid through the nozzle 32. Means are provided for checking the opening and closing movements of the stem 41 in order to prevent abrupt changes in the mixture. To this end the upper end of the stem 41 is provided with a piston 46sliding within a cylinder 47. As shown clearly in the drawing the cylinder is threaded within an opening formed in the upper 'portion of the carbureter casing and is provided with a lower bearing in which the stem 41 is slidingly received. The dash pot chamber 50 is provided with passages 51 which permit the gradual escape or intake of air during the movements of the piston. The head of the cylinder' is conveniently closed by a threaded cap 52.

lIt may be advisable when the motor is initially started and exhaust gases are not available for heating to provide an auxiliary heater in the mixing chamber. In the present invention this heater which is of the electric type is conveniently controlled from the air intake valve 6 so that the'closing of the valve to give a rich mixture will at the same time start the heater. The pivot for the valve 6 is provided with an arm G0 connected with an arm G1 through the link G2. The arm 61 extends from the shaft 63 which carries a contact disk 64 havingV an-V insulating portion y67 and a conducting portion 68 adapted to engage a stationary contact 65 to close the circuit through the heater 66.

Vhile it is preferred to employ the speciic construction and arrangement of parts shown and described, it will be understood that this construction land arrangement is not essential except so far as specified in the claims, and may be changed or modified without departing from the broader features of the invention.

The invention having been described, what is claimed is:

1. A carbureter, having in combination. aI mixing chamber, a primary fuel nozzle located in the mixing chamber, a secondary fuel nozzle supported at the same heightas the primary nozzle, an auxiliary air valve controlled by the suctionv within the intake manifold. a spring for normally retaining the air valve closed. a dash pot for retarding the movements of the air valve and a needle valve operated by the. air valve and conpair ofVenturi tubes, a liquid nozzle located sage of the saidair through the oat chamwithin' each tube, a float chamber, conuecber, and means for conducting the exhaust tions betweenthe float chamber vaud the gases about the Venturi tubes to finally heat 10 liq'uid nozzles, an air passage leading the mixture of fuel and air.

5 through the Hoat chamber and communicatl n ing with the'tubes, means for heating the WARD R. GOODALE. air .bythe exhaustl gases prior tothepas- MAURICE L. BULLARD. 

